Pressure apparatus for dental castings.



H. SOHWEITZER. PRESSURE APPARATUS FOR DENTAL GASTINGS.

APPLICATION FILED DBO. 30, 1912.

Patented Aug. 11, 1914.

WITNESSES UNITED STATES PATENT OFFICE.

PRESSURE APPARATUS FOR DENTAL CASTINGS.

Specification of Letters Patent.

Patented Aug. 11, 1914.

Application filed December 80, 1912. Serial No.739,266. v

To all whom it may concern Be it known that I, HEINRICH SCHWEITZER, a subject of the German Emperor, residing at New York, in the county and State of New York, have invented new and useful Improvements in Pressure Apparatus for Dental Castings, of which the following is a specification.

Casting apparatus operated with, a gaseous pressure medium such as air or compressed gas usually have a flask containin'g the mold and a cover sealing the flask. A central perforation in the flask cover is used for the passage of the fluid pressure medium into the flask. It has been found a disadvantage to force an air current directly upon the liquid metal and therefore it was suggested to use a diaphragm provided with several holes at the end of the centralperforation as shown in the Figures 1 and 2 of the accompanying drawing. Such holes did not allow a uniform concentric pressure in the flask and it happened-very often that one or more of the holes were obstructed and vertical section of a flask cover illustrating the old construction of several holes in a diaphragm at the end of the vertical perforation of a flask cover. Fig. 2 is a bottom view of the flask cover shown in Fig'. 1. Fig. 3 is the lateral view with parts in section ofa casting apparatus having a flask, and cover in the central perforation of which a disk like body is fixed. Fig. 4 is a sectional view of a flask cover without an air dispersing body. Fig. 5 is a lateral view of Fig. 9 shows another modified way of fining adisk like body atthe end of the central perforation of a flask cover; Fig. 10 is the bottom view of the flask cover shown in Fig. 9.

A uniform distribution of the fluid pressure medium in a pressure flask for castings is obtained by the arrangement of an annular slotin the flask cover concentric to the central perforation. Such annular slot requires the presence of a body which is fastened at the end of the central perforation and most preferably has a disk like shape. Various means of fastening the disk like body at the end of the perforation are shown in the accompanying drawing. In the preferred construction shown in the Figs. 3 to 6 I connect a hollow screw spindle, S, with the center of a disk, D, by a tubular piece, T,

perforated at O -O The interior of the connection piece,'T, communicates with the ,hole, 0', of the screw spindle, so that the pressure medium will pass from the source the spindle, S, then through the lateral perforations, 0 -0 in order to enter the interior of the flask by the annular vent, V.

conically enlarged (Fig. 4, B) and the disk conically beveled (Fig. 6, B The screw spindle, S, can be set in its end, U, against a shoulder, U in the flask cover, C. A similar construction shown in Fig. 7 necessitates the presence of a perforated diaphragm, M, in the center of which a solid connection piece, P, is fastened carrying at its lower end the disk, D.

end of the central perforation, R, is illustrated in Figs. 9 and 10 where the disk, D, is set against the cover, C, opposite the opening, R, by meansof screws or rivets, YY, and an open vent may be maintained by the washers, WW. Without the washers, WW, the disk D, will act like a valve.

'of great advantage as it distributes the pressure medium most uniformly, causlng presuniformly from all sides. p

Having now fully descrlbed. my invention I claim:

A casting apparatus adapted to be operwhich is reduced in diameter and laterally The end of the central perforation may be A circular vent in diverging direction is of pressure first through the hole, 0, of

A modified way of fixing a disk, D, at the sure action upon the liquid metal to be cast ated with gaseous pressure medium having and plug for the purpose of discharging the a flask and a cover provided with a'central pressure medium in diverging direction subperforation, the lower end of said perforastantially as described and shown. 7

tion being of conical shape, and a plug be- 1 'HEINRICH SCHWEITZER. 5 ing conical shaped in its lower end; said Witnesses: plug fastened on said cover in such manner WM. H. KRUSE,

that an-annular slot is left between c'0 ver J. A. BLUHM. 

